Cyclodextrin combines with various guest compounds in aqueous solutions to form structurally specific inclusion compounds. Thus, cyclodextrin containing solid membranes are expected to have unique performance, particularly in terms of separating and permeating capabilities and cyclodextrin, if it is supported on high polymers, is anticipated to exhibit various physical properties that have been impossible to obtain when it is used alone; since this brings about the advantage of expanded applications, it has been desired to develop a method by which cyclodextrin-containing membranes can be freely prepared.
As regards the preparation of such cyclodextrin membranes, Unexamined Published Japanese Patent Application No. 232210/1985 discloses a method in which the crystal of a cyclodextrin inclusion compound and a high polymer comprised of a compound having an isocyanate group are cast onto a commercial ultrafiltration membrane, and Unexamined Published Japanese Patent Application No. 258702/1987 discloses a method in which cyclodextrin reacted with a variety of monomers is copolymerized with acrylonitrile derivatives to obtain high polymers, which are then processed into membranes by known methods.
However, the method disclosed in Unexamined Published Japanese Patent Application No. 232210/1985, supra has the disadvantage that the cyclodextrin membrane cannot be used as the membrane of high polymer per se, whereas the method disclosed in Unexamined Published Japanese Patent Application No. 258702/1987 has had the problem that the degree of introduction of cyclodextrin in the obtained membrane of high polymer is so low as 3-4% that satisfactory characteristics cannot be achieved.
Therefore, the object of the present invention is to provide a method of synthesizing cyclodextrin polymers that enables cyclodextrin to be contained as introduced to high levels.
It is also the object of the present invention to provide a process for producing cyclodextrin membranes that contain cyclodextrin as introduced to high levels and that can be used on their own.